Femoral and tibial component rotation in total knee arthroplasty: methods and consequences

At least four ways have been described to determine femoral component rotation, and three ways to determine tibial component rotation in total knee replacement (TKR). Each method has its advocates and each has an influence on knee kinematics and the ultimate short and long term success of TKR. Of the four femoral component methods, the author prefers rotating the femoral component in flexion to that amount that establishes a stable symmetrical flexion gap. This judgement is made after the soft tissues of the knee have been balanced in extension. Of the three tibial component methods, the author prefers rotating the tibial component into congruency with the established femoral component rotation with the knee is in extension. This yields a rotationally congruent articulation during weight-bearing and should minimise the torsional forces being transferred through a conforming tibial insert, which could lead to wear to the underside of the tibial polyethylene. Rotating platform components will compensate for any mal-rotation, but can still lead to pain if excessive tibial insert rotation causes soft-tissue impingement.

The evolving incidence and reasons for re-operation after fixed-bearing PCL retaining total knee arthroplasty

PCL retaining fixed-bearing TKA is a highly successful operation with the need for more surgery occurring at the rate of approximately 0.4% per year over the first 27 years. The most common cause for revision surgery is related to polyethylene insert failure and accounts for approximately 50% of re-operations. Late metastatic infection is the next most frequent cause followed by patellar problems, late instability and component loosening in decreasing frequency. A myriad of rare miscellaneous problems can also occur.

Self-expanding metal stent insertion for inoperable esophageal carcinoma in Belfast: an audit of outcomes and literature review

Successful palliation of dysphagia in patients with inoperable esophageal carcinoma has a major effect on quality of life. Self-expanding metal stents (SEMS) are currently recommended for rapid symptomatic relief when life expectancy is less than 3 months. We assessed complication and reintervention rates along with survival outcomes in patients with inoperable esophageal carcinoma undergoing stent insertion. A retrospective audit was performed from April 2007 to June 2009 for all inoperable primary esophageal carcinoma patients who had an esophageal stent inserted for dysphagia. Case notes were reviewed for clinical, pathological, stent and complication details, while ICD-10 causes of death were obtained from the Department of Health and Social Services, Northern Ireland. Fifty-six stents were inserted into 53 patients (66.0% male, mean age of 70 years). Inoperability was defined by metastatic spread (n= 34, 64.2%), locally advanced disease (n= 7, 13.2%), and severe medical comorbidities (n= 12, 22.6%). The median time from diagnosis to stent insertion was 109 (interquartile range [IQR] 43-187) days. Fifty stents (94.3%) were successfully deployed, while three patients (5.7%) required an additional stent as the primary stent had not bridged the tumor (proximal deployment = 2, suboptimal stent length = 1). Post-SEMS dysphagia scores were significantly better than pre-SEMS scores (2.90 vs. 1.54, P < 0.001). There were 27 complications identified in 23 (43.4%) patients (major complications = 9, minor complications = 14). Twelve patients (22.6%) required additional endoscopic procedures. The 30-day mortality rate was 11.3% (n= 6). Only one patient (1.9%) remains alive with a cumulative median survival rate of 84 (IQR 38-156) days. Esophageal stent insertion in this group of patients still presents a clinical challenge, with complication and endoscopic reintervention rates of 43.4 and 22.6%, respectively. Our results are comparable with previously published series, and as a palliative modality stent insertion remains appropriate when expected survival is less than 3 months. A range of SEMS is currently available with broadly similar efficacy and safety profiles. Data regarding the newly available fully covered SEMS suggest that they should be avoided.

Measuring the economic costs of antimicrobial resistance in hospital settings: summary of the Centers for Disease Control and Prevention-Emory Workshop

Health systems administrators and clinicians need refined calculations of the attributable cost of infections due to drug-resistant microorganisms to develop and assess cost-effective prevention strategies that deal with these infections. To date, however, efforts to provide this information have yielded widely variable and often conflicting estimates. This lack of reproducibility is largely attributable to problems in study design and in the methods used to identify and measure costs. Addressing these methodological issues was the focus of a workshop that included participants from a broad range of backgrounds, including economics, epidemiology, health care management, health care outcomes research, and clinical care. This workshop summary presents the advantages and disadvantages of various research designs as well as particular methodological issues related to the measurement of the economic cost of resistance in health care settings. Suggestions are made for needed common definitions and approaches, study areas for future research are considered, and priority investigations are identified.

Tibial osteotomy coincident with long stem total knee arthroplasty: a surgical technique

Tibial deformity secondary to previous fracture or osteotomy requires corrective osteotomy in some patients undergoing total knee arthroplasty (TKA). This can be performed in either two stages or coincident with the arthroplasty. Literature on coincident tibial osteotomy and TKA has been published previously, but details of the complicated surgical technique are lacking for surgeons performing this procedure for the first time. This article details the preoperative planning involved and the intraoperative technique used in tibial osteotomy coincident with TKA.

Applying economic principles to health care

Applying economic thinking to an understanding of resource use in patient care is challenging given the complexities of delivering health care in a hospital. Health-care markets lack the characteristics needed to determine a "market" price that reflects the economic value of resources used. However, resource allocation in a hospital can be analyzed by using production theory to determine efficient resource use. The information provided by hospital epidemiologists is critical to understanding health-care production processes used by a hospital and developing economic incentives to promote antibiotic effectiveness and infection control.

Persistent limp after total hip replacement: one step at a time

A limp can be a significant sign of serious pathology about the hip. The source of the limp can be the hip or remote from the hip. Careful evaluation of each individual patient can lead to the discovery of the cause and, hopefully, its resolution.

A comparison of 4 intraoperative methods to determine femoral component rotation during total knee arthroplasty

A total of 100 consecutive posterior cruciate-retaining total knee arthroplastics were performed in 81 patients with an average age of 69 years by 1 surgeon. Diagnoses included osteoarthritis in 93 knees and rheumatoid arthritis in 7 knees. The femoral alignment necessary to create a rectangular flexion gap was determined and compared with Whiteside's line, the transepicondylar axis, and a line in 3 degrees of external rotation relative to the posterior condyles of the femur. The transepicondylar axis most consistently recreated a balanced flexion space, whereas 3 degrees of external rotation off the posterior condyles was least consistent, especially in valgus knees.

Total knee arthroplasty with posterior cruciate retention in patients with rheumatoid arthritis

The objective of the present study was to evaluate posterior cruciate ligament retention in total knee arthroplasty for patients with rheumatoid arthritis to determine long term ligamentuous stability. The study concerns an average 11-year followup (range, 10-13 years) of 52 patients (81 knees) with rheumatoid arthritis who had a total knee arthroplasty using a contemporary posterior cruciate retaining prosthesis. Particular attention was given to component survivorship and clinical stability. Fourteen patients (20 knees) died; none of these patients required revision surgery. No patients were lost to followup. Sixty-one knees in 38 patients were examined. In this group, the Knee Society knee score averaged 95 points (range, 63-100 points) and function score averaged 74 points (range, 0-100 points). Postoperative flexion averaged 112 degrees and extension averaged 0 degree. Four knees had 3 degrees asymptomatic hyperextension; one knee with 5 degrees hyperextension occasionally gave way. Five well aligned knees had between 6 degrees and 9 degrees varus or valgus laxity in extension, but no patient reported subjective instability. Two patients underwent revision surgery. One patient had a worn metal backed patella component replaced and the other patient had an open synovectomy for recurrent active rheumatoid synovitis. Thirteen-year survivorship based on need for revision surgery was 97% with the 95% confidence limits between 88% and 100%. There was no radiographic loosening or subsidence of prosthetic components. At 11-year followup, patients with rheumatoid arthritis whose knees were replaced with posterior cruciate retention prostheses experienced results equivalent to or better than those reported for patients with osteoarthritis at a similar followup. Late hyperextension and subsequent instability may be a concern in the second decade of followup.

Selective patellar nonresurfacing in total knee arthroplasty. 10 year results

Patella nonresurfacing in total knee arthroplasty was reviewed retrospectively in 49 knees (42 patients). Thirteen patients (17 knees) died leaving 29 patients (32 knees) in the final study group. The minimum length of followup was 10 years and averaged 11.7 years (range, 10-13.4 years). The diagnosis was primary osteoarthritis in 26 knees, posttraumatic arthritis in four, osteonecrosis in one, and Paget's disease in one. Patients were evaluated using the Knee Society score, a patella score, and radiographs. The mean Knee Society score improved from 52.8 to 87.5 points postoperatively and functional score improved from 57.5 to 84.5 points postoperatively. Anterior knee pain was reported in six knees (20%). Only one patient required secondary resurfacing of the patella because of postoperative anterior knee pain. No significant correlation was found between anterior knee pain and patellofemoral joint space, patellar sclerosis, Insall-Salvati ratio, patellar tilt, gender, obesity, or age. Based on the need for secondary patellar resurfacing because of anterior knee pain, the 10-year survival was 97.5%. At minimum 10-year followup, retaining the patella in total knee arthroplasty in selected patients with osteoarthritis of the osteoarthritic knee can yield acceptable results.

The Ranawat Award. Femoral component rotation during total knee arthroplasty

One-hundred consecutive posterior cruciate retaining total knee arthroplasties were performed by one surgeon in 81 patients with an average age of 69 years. Diagnoses included osteoarthritis in 93 knees and rheumatoid arthritis in seven. The femoral alignment necessary to create a rectangular flexion gap was determined and compared with Whiteside's line, the transepicondylar axis, and a line in 3 degrees external rotation relative to the posterior condyles of the femur. The transepicondylar axis most consistently recreated a balanced flexion space whereas 3 degrees external rotation off the posterior condyles was least consistent especially in knees in valgus.

Kneeling ability after total knee arthroplasty. Perception and reality

Kneeling as one of the knee's capabilities required for many activities of daily living has not been examined in detail after total knee replacement. The purpose of the present study was to question the patients' ability to kneel and their perception of factors affecting this ability after total knee arthroplasty, and to objectively assess their kneeling ability. Seventy patients with 100 total knee arthroplasties were asked to comment on their ability to kneel. Thirty-one patients with 44 knees said they could kneel easily, 29 patients with 41 knees said they were able to kneel but avoided doing so, and 10 patients with 15 knees said they were unable to kneel. Regarding observed kneeling ability, all patients were able to kneel under supervision: 56 patients with 82 knees knelt easily and got up easily from this position, 11 patients with 14 knees showed slight difficulties in kneeling or in getting up, and three patients with four knees had marked difficulties with kneeling. The patients' perceived ability to kneel after total knee arthroplasty was less than their observed ability. Fear of harming the prosthesis and lack of information prevented kneeling in 49% of the patients (27 of 56 knees) with perceived inability to kneel. Of those patients with observed difficulty in kneeling, scar pain and back related problems seemed to be major factors in limiting the kneeling ability. Kneeling, as an important function of the knee, should be given additional consideration in relation to the functional results of total knee arthroplasty. Patients should be counseled regarding factors affecting future ability to kneel.

Total knee arthroplasty in patients with rheumatoid arthritis. An overview

Total knee arthroplasty in patients with rheumatoid arthritis presents several unique challenges. Patients with rheumatoid arthritis often have additional medical, anesthetic, and global musculoskeletal problems that are not present in the patient with osteoarthritis. In terms of the knee, these patients usually have osteopenia and may present with an array of bone and soft tissue deformities, each of which can impact the initial success and long term durability of a total knee replacement. Despite these potential difficulties, the early and long term results of total knee arthroplasty in patients with rheumatoid arthritis have proven to be excellent.

Synovial cyst of the proximal tibiofibular joint with peroneal nerve compression after total knee arthroplasty

Synovial or ganglion cysts of the proximal tibiofibular joint are less common than synovial cysts of the knee joint but may present in a similar manner and may be difficult to diagnose clinically. Although synovial cysts arising from the knee joint after prosthetic arthroplasty have already been described, we report a case in which a lateral knee mass compressing the peroneal nerve was found to be a synovial cyst arising from the tibiofibular joint.

Humeral hemiarthroplasty of the elbow joint in young patients with rheumatoid arthritis: a report on 7 arthroplasties

This article evaluates the early results of 7 humeral hemiarthroplasties of the elbow joint in 5 female rheumatoid patients using only the humeral component of the capitellocondylar prosthesis. The follow-up period was 25 to 109 months. All patients were 50 years old or younger; 3 patients were between 22 and 26 years. Because all patients were rather young, the intention was to perform a procedure that conserves a maximal amount of bone stock for future salvage procedures. One prosthesis had to be removed because of an infection unrelated to the primary procedure. The remaining bone stock provided a stable and pain-free excision arthroplasty. The other arthroplasties showed good pain relief; however, postoperative motion was not as reliable as described for total capitellocondylar prostheses.

Prodromes of failure in total knee arthroplasty

A total of 102 revision total knee arthroplasties (TKAs) were reviewed to determine the prodromal symptoms and radiographic findings associated with failure. Presenting symptoms included pain (84%); swelling (76%); progressive varus or valgus deformity (19%); instability (17%); stiffness (17%); clicking or grinding (7%); catching (4%); and patellar pain, subluxation, or clicking (4%). Radiographs were diagnostic in 91% of cases, demonstrating complete radiolucencies (80%), polyethylene wear (43%), component breakage (5%), metallic debris (3%), patellar subluxation or dislocation (4%), and osteolysis (4%). Gross intraoperative findings included polyethylene wear (72%), osteolysis (22%), metal-wear synovitis (9%), component breakage (6%), patellar wear and dissociation (4%), and occult sepsis (5%). The average duration of symptoms was 13 months; the interval between orthopedic evaluations averaged 23 months. Based on this information, we recommend that an annual questionnaire and weight-bearing radiographs be used to ensure adequate surveillance of TKA patients and avoid complications associated with delay in diagnosis of polyethylene wear or implant loosening.

In vivo anteroposterior femorotibial translation of total knee arthroplasty: a multicenter analysis

A study was conducted to determine in vivo femorotibial contact patterns for subjects having a posterior cruciate retaining or posterior cruciate substituting total knee arthroplasty. Femorotibial contact of 72 subjects implanted with a total knee replacement, performed by five surgeons, was analyzed using video fluoroscopy. Thirty-one subjects were implanted with a posterior cruciate retaining total knee replacement with a flat polyethylene posterior lipped insert, 12 with a posterior cruciate retaining total knee replacement with a curved insert, and 29 with a posterior cruciate substituting total knee replacement. Each subject performed successive deep knee bends to maximum flexion. Video images at 0 degree, 30 degrees, 60 degrees, and 90 degrees flexion were downloaded onto a workstation computer. Femorotibial contact paths were determined for the medial and lateral condyles using an interactive model fitting technique. Femorotibial contact anterior to the tibial midline in the sagittal plane was denoted as positive and contact posterior was denoted as negative. Analysis of average femorotibial contact pathways of both posterior cruciate retaining designs revealed posterior femorotibial contact in full extension with anterior translation of femorotibial contact commonly observed in midflexion and terminal flexion. In posterior cruciate substituting designs, anterior femoral translation was seen medially at 30 degrees to 60 degrees flexion but rarely was observed laterally. Posterior femoral rollback laterally from full extension to 90 degrees flexion was seen in 100% of subjects implanted with a posterior cruciate substituting total knee replacement, versus 51.6% (posterior lipped polyethylene insert) and 58.3% (curved insert) of those with a posterior cruciate retaining total knee replacement. Data from this multicenter study are remarkably similar to previous fluoroscopy data from a single surgeon series, showing a lack of customary posterior femoral rollback in both posterior cruciate retaining designs, and conversely showing an average anterior femoral translation with knee flexion. Posterior femoral rollback, less than in normal knees, routinely was observed in posterior cruciate substituting total knee arthroplasty, attributed to engagement of the femoral component cam with the tibial post. The abnormal anterior femoral translation observed in posterior cruciate retaining total knee arthroplasty may be a factor in premature polyethylene wear observed in retrieval studies.